document.write( "Question 980070: Two trains made the same 150-mile run. Since one train traveled 20 mph faster than the other, it arrived 2 hours earlier. Find the speed of each train. \n" ); document.write( "
Algebra.Com's Answer #601276 by ikleyn(52769)![]() ![]() You can put this solution on YOUR website! \r \n" ); document.write( "\n" ); document.write( "Let u be the speed of the faster train in mph (miles per hour).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Then the speed of the other train is u-20 mph.\r \n" ); document.write( "\n" ); document.write( "We have an equation\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Solve this equation by simplifying it step by step:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "You can solve this quadratic equation by using quadratic formula (see the lesson Introduction into Quadratic Equations in this site). \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Or, you can solve it by applying the Viete's formula (see the lesson Solving quadratic equations without quadratic formula in this site). \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "In any case, the roots of the quadratic equation are \n" ); document.write( "\n" ); document.write( "Only positive value of the speed has the sense in this problem, so that the solution is u = 50 mph.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Answer. The speed of the faster train is 50 mph. The speed of the other train is 30 mph. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |